Burglar-alarm.



F. R. KAWAHARA.

BURGLAR ALARM.

APPLICATION FILED JULY 3. I915.

Patented. Dec. 5, 1916.

F'ranJd R. Jfivewaharw FRANK a KAWAHARA, or Los ANGELES, camroanm.

BURG IiAR-ALARM.

Specification of Letters Patent.

PatentedDec. 5, iaic.

Application filed July 3, 1915. Serial No. 38,032.

It is an object of this invention to provide a burglar alarm, which upon being set in operation, will continue to'give a signal, and which cannotbe placed out of operation by the burglar.

It is another object of this invention to provide'a compact burglar alarm which may be operated by a mechanical motor contained within a housing inclosing the entire mechanism. 1 I I It is a still further object of this invention to provide a simple burglar alarm. which can be easily reset for operation'by one possessing a key to a housing which incloses the mechanism. U j

T accomplish these objects by means of the embodiment of myinvention illustrated in the accompanying drawing, in which:

Figure 1 is a perspective view showing a fragment of a frame and window with my improved burglar alarm attached thereto. Fig. 2 is a side elevation of my improved burglar alarm with parts broken away to partly illustrate the mechanism. Fig; is a section taken on the line 33 of Fig.- 2

. looking in the directionof the arrows. Fig.

4 is a fragmentary'view showing a section taken on the lineHofFig. 2. Fig.5 is a detail section taken on the line 5-5 of Fig. 3. Fig. 6 is a view of a stop rod as seen on the line 55 of Fig. 3.

More specifically, 6 indicates a window frame which is provided with sliding windows 7. Fixedly secured to the frame 6 by any suitable means is my improved alarm indicated generally by 8. Upon the window sash is mounted a member 9 for detachably securing a flexible chain 10 which connects the burglar alarm and the window. Member 9 is provided with a flange 11 which is constructed to form a channel open at one end and is designed to receive a button 12 connected to the end of chain 10. This construction is common in chain locks which are used to permit a door to be opened a limited amount. Secured to one end of chain 10 is a latch 13 which is provided with a bolt portion let designed to cooperate with the keeper on the stop which is later described.

' I have illustrated my burglar alarm as I operated by a spring motor. A clock spring 15 of the usual type has one end secured to a frame 16 and the other end secured to a shaft 17. Freely mounted upon-shaft 17 is a gear 18 provided with a pawl 19 and a spring 20 which presses the former against the teeth of a ratchet wheel 21 fixedly mounted upon shaft 17. Shaft 17 is provided at its outer end with a key 22 for winding the spring. The construction being of the type common in clocks.

*rame 16 is securely mounted upon the base 23 by means of bolts 24:, 25 and 26. Bolt 26 extending beyond frame 16 and supporting a frame 27 which is so arranged as to prevent the spring 15 from moving transversely as it expands. The gear for operating the audible alarm is positioned between base 23 and frame 16 and comprises ashaft 27 upon which is fixedly secured a pinion meshing with gear 18. Also. secured upon shaft 27 is a gear wheel 28 which meshes with a pinion fixedly secured on shaft 29. Fixedly' secured to shaft 29 is an escapement wheel 30. v

The gear and motor mechanism just described may be varied to suit the particularform of housing in which it is desired to place theoperating structure, and is not a material part of my invention, except that an escapement wheel is necessary to be geared to the source of power. I I,

Pivotally mounted between the base 23 and frame16 upon a shaft 31 is an anchor 32; the arms of which engage the escape ment wheel 30. Secured to shaft 31 is a clapper 33 having a hammer 3 1 arranged to strike a bell 35. Bell 35 being of a cup form and overhanging the operating mechanism. Depending from anchor 32 is an arm 36 which is normally engaged by a stop pin 37 secured to a rod 38 which is extended through the casing. Rod 38 is provided with an enlarged portion 39 and a collar 40. The enlarged portion 39 which extends through an opening in the bell 35 and a housing 41 is provided at its outer end with a keeper t2 designed to be engaged by the bolt 14 to maintain the stop pin 37 in engagement with the arm 36 of the anchor. A spring 43 is disposed between the collar 40 and the housing 41 for moving stop pin 33 out of engagement with the anchor when the bolt 14 is Withdrawn.

I have provided a convenient means for moving the stop rod 38 into position such that the keeper 42 may be engaged by the bolt 14 after release of the stop rod by the bolt and comprises a shaft 44 having upon its end a key 45 and a pinion 46 which engages a rack 47 upon the stop rod 38. To set the burglar alarm into operation the key is turned to rotate the pinion 46 and move the stop rod 38 outward. The bolt 14 is then positioned behind the keeper 42.. A shield 48 protects keeper 42 and the bolt '14, and a guide 49 for the chain is shown disposed upon thehousing. A bracket 50 mounted upon frame 27 supports the bell 35 per mitting no interference with its tone. The entire structure is covered by a housing 41 having openingsol in the cylinder wall thereof covered by a screen or other reticu lated plates permitting the sound waves to pass readily therethrough. A cover preferably attached by hinges not shown is provided With a lock indicated generally by 53. The cover is provided With apertures 54 covered by screen or reticulated plates.

It is obvious that the housing just de scribed covers the entire operating, mechanism so that the key 45 for setting the alarm cannot be tampered With, and is only accessible to one possessing the key to the cover. Key 22 for'winding is also protected by the housing.

In the operation of my burglar alarm, the window. 7 having been closed, the button is slipped in the flanged portion of member 9. Key 45 is rotated to force the keeper 42 out? side of the casing 41 and the bolt 14 is placed behind the keeper. The spring is then wound by means of key 22 and the cover to the housing closed and locked. It will be apparent that in the position of the stop rod 38 where the burglar alarm is set, the stop pin 37 engages arm 36 and prevents i I J l the anchor from oscillating. Upon the window being opened chain 10 pulls member 13 and bolt 14 from behind the keeper 42. The spring 43 acting against collar 40 forces the stop pin 37 away from the anchor arm 36 permitting the oscillation of the anchor and a consequent movement of the clapper 33 sounding an alarm upon the bell The stop rod 38 cannot be reached from the outside of the housing, and therefore the alarm will continue to ring.

What I claim is:

1. In a burglar alarm, the combination of an alarm mechanism comprising a source of power, a shaft driven therefrom, an escapement wheel on said shaft, an anchor pivotally mounted to engage said escapement wheel, an alarm controlled by said anchor, a stop for locking said anchor provided with a rack, resilient means engaging said stop for moving it out of locking position, a pinion engaging said rack and provided with an arbor; a casing inclosing said alarm mechanism having an aperture through which said step may be projected, and a latch disposed outside of said casing detachably engaging said stop.

2. In a burglar alarm, the combination of an alarm mechanism, comprising a source of power, a shaft driven therefrom, an escapement wheel on said shaft, an anchor pivotally mounted to engage said escapemcnt wheel, an alarm controlled by said anchor, a stop for said anchor having a keeper at the end thereof and a rack at the opposite end, resilient means engaging said stop for moving it out of locking position, a pinion engaging said rack provided with an arbor; a casing inclosing said alarm mechanism havingan aperture through which said stop may be projected, a shield for said aperture; and a latch disposed outside of said casing having a tongue for engagement with the keeper on said stop rod.

In witness that I' claim the foregoing l have hereunto subscribed my name this 7th day of June, 1915.

FRANK R. KAWAHARA.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

